I'll be in Zurich next week at Jazoon giving a presentation (from 2-2:40pm) on the Tango features in the GlassFish Metro web services stack.

I'll be showing interoperability between the Metro stack and the Microsoft's WCF stack in .NET 3.0.

By-the-way: these features (i.e., eliable messaging, atomic transactions, security, secure conversation, trust) work just fine in Java-only scenarios. You don't need WCF to take advantage of this work.